Square can seaming head



Jam l942- A. L. KRONQUEST ETAL 2,271,153

SQUARE CAN SEAMING HEAD I Filed Nov. 27, 1939 6 Sheets-Sheet 1 .z 'i Z Jan. 27, 1942. A. L. KRONQUEST ET AL 2,271,153

SQUARE CAN SEAMING HEAD Filed Nov. 27, 1939 6 Sheets-Sheet 2 R \K *1 A Q Q3 5 L; Q x A g m N Q *1 i a N g R T\\ 1 Illum- Q 71% A:

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Jan. 1942- A. L. KRoNQuEs-i' ET AL 3 SQUARE CAN SEAMING- HEAD Filed Nov. 27, 1939 6 Shets-Sheet s Jan. 27, 1942. A. 1.. KRONQUEST ET AL SQUARE CAN SEAMING HEAD Filed Nov. 27, 1939 6 Sheets-Sheet 4 Jan. 27, 1942. A. 1.. KRONQUEST ET AL 2,271,153

SQUARE CAN SEAMING HEAD Filed Nov. 27 1939 6 Sheets-Sheet 5 Jan. 27, 1942. A. L. 'KRONQUEST ET AL 2,271,153

SQUARE CAN SEAMING HEAD Filed Nov. 27, 19:59 6 Sheet s-Sheet s F l/ l: 1 76;? 2

Patented Jan. 27, 1942 SQUARE CAN 7 SEAMING HEAD Alfred L. Kronquest and Otto A.

Schmitt,

Syracuse, N. Y., assignors to Continental Can Company, Inc., New York, N. Y., a corporation of New York Application November 27, 1939, Serial No. 306,366

4 Claims.

The invention relates generally to can making machinery and primarily seeks to provide a novel and efficient seaming head for seam-securing end closures upon container bodies of the oblong or generally square type.

More particularly, the invention seeks to provide certain new and useful improvements in seaming head equipments of the type disclosed in the application for U. S. Letters Patent filed by Alfred L. Kronquest, Serial No. 210,742, filed May 28, 1938, and to embody those improvements in a seaming head adaptable for use in the container and end closure assembling machine disclosed in the copending application for U. S. Letters Patent, filed by Otto A. Schmitt November 10, 1939, Serial No. 303,991.

Machines have heretofore been devised for seaming end closures upon containers of the type stated, but considerable difficulty has been experienced in forming seams about the edges of generally square containers so that the seams are uniform at all points, and containers assembled on such machines have been found to include seams properly tight at some corners and objectionably loose at others. The conditions complained of were largely remedied in the structure disclosed in the Kronquest patent application above referred to, and in the present disclosure there are disclosed novel features of structure and arrangement which additionally assure the formation of uniformly tight seams and facilitate operation and servicing of the seaming head.

Another object of the invention is to provide a seaming head mounted in the manner stated, and

novel driving connections for the operating parts of the head which will not be disrupted by movement of the head upon its pivotal mounting.

Another object of the invention is to provide a novel seaming head of the character stated'in which is provided a stationary chuck member surrounded by a seaming lever control groove, lever arms bodily movable with the head and having rollers movable in the control groove to position the levers relative to the chuck member, seaming arms pivoted on the levers and carrying first and second operation seaming rolls movable toward and from the chuck member, and means for moving the seaming arms including individual positively rotated cam elements effective to force the first operation roll equipment against the chuck member in a plurality of definite successive stages. I

Another object of the invention is to provide a seaming head of the character stated in which the first and second operation rolls are arranged in opposed pairs, in which the first operation rolls are simultaneously and positively forced against the chuck member in a plurality of definite successive stages by rotary cams having a plurality of steps thereon separated by dwell portions, and in which the second operation rolls are simultaneously and positively forced full distance against the chuck by rotary cams having single step and dwell portions.

Another object of the invention is to provide a novel seaming head structure mounted in the manner stated and including a novel casing arrangement and cooperating free swinging mountings for the seaming levers designed to facilitate servicing of the seaming equipments.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more fully understood by following the detailed description, the appended claims, and the several views illustrated in the accompanying drawings.

In the drawings:

Figure 1 is a vertical longitudinal section through a container assembling machine embodying the invention, the section being taken along the plane of the axis of the seaming head and the seaming head being shown in elevation.

Figure 2 is an enlarged vertical longitudinal section through th axis of the seaming head.

Figure 3 is a vertical longitudinal section taken through the axis about which the seaming head is pivotally mounted.

Figure 4 is a detail vertical cross section taken on the line 4-4 on Figure 3.

Figure 5 is an enlarged end elevation of the seaming head looking into the open end thereof, the swingable mounting of the lever arms being illustrated in dot and dash lines.

Figures 6 and '7 are detail face views respectively illustrating the first and second operation roll actuating cams.

Figures 8 and 9 are diagrammatic developments of the cams shown in Figures 6 and 7.

Figures 10 to 14 are fragmentary diagrammatic sectional views illustrating the first operation seaming functions respectively accomplished at points a, b, c, d and e on the cam development of Figure 8.

Figures 15 to 17 are fragmentary diagrammatic sectional views illustrating the second operation seaming functions respectively accomplished at points a, b, and c on the cam development of disposed in suitable bearings in the frame, and a pocketed turret I is secured upon one end of a shaft rotatably mounted in a horizontal bearing |2 on the machine frame and equipped at its other end with a disk l3 from which indexing rollers project in equidistantly spaced relation for being engaged by an indexing cam l4 which serves to impart step-by-step rotation to the turret for presenting the pockets thereof at the various stations provided in the machine. The cam I4 is mounted on the upper end of a shaft I5 supported in a vertical bearing IS on the machine frame and driven by a gear couple I! from a shaft I8 vertically supported in bearings I9 in the frame and in turn driven by a worm gear couple from the shaft See Figure 1.

Loosely assembled container body end closure elements generally designated 2 i, when presented at the securing or seaming stations at the bottom of the turret as illustrated in Figure 1 of the drawings, are engaged by a chucking pad 22 and are moved thereby from the position illustrated in Figure 1 toward the right for the purpose of engaging the container with the chuck of the seaming mechanism so that the end closure can be seam-secured to the container body in the manner hereinafter described. The chucking pad 22 is adjustably mounted on a slide head 23 reciprocably supported on the frame and'having roller connection as at 24 with a grooved plate cam 25 secured upon the upper end of the shaft l8 and through the medium of which the desired reciprocation is imparted to the pad 22.

The seaming head proper which comprises the r main subject matter of the present invention includes upper and lower casing sections 23 and 21 including laterally extended housing portions respectively designated 28 and 29, and these sections 26, 28 and 21, 29 are flange-secured together T as at 30. The sections 26 and 2'! thus secured form a large open-ended bell portion 3| in which the seaming mechanism proper operates. See Figures 1, 2 and 4.

A part of the upper portion of the bell 3| is hinge-mounted as at 32 so that it can be swung upwardly in the manner illustrated by dot and dash lines in Figure 5 of the drawings to facilitate access to the interior of the bell and the mechanism therein.

A pivot sleeve or standard 33 depends from the lower head section 21, 29, and it will be observed by reference to Figures 1 and 4 of the drawings that the axis of this sleeve is disposed to one side of the axis of the bell portion 3| of the seaming head housing. The housing sections 26, 28 and 21, 29 together provide a bearing hub portion 34 and a bearing hub portion 35, the purposes of which will be described later. The pivot standard 33 is pivotally mounted in the bearing sleeve 8 formed on the machine frame, and the weight of the seaming head is supported in this bearing on an anti-friction bearing equipment 36 interposed between the upper end of the bearing sleeve and the opposed portion of said housing in the manner best illustrated in Figures 1, 3 and 4 of the drawings.

By reason of the provision of the pivot standard and sleeve bearing equipments 33, 8; it is possible to swing the seaming head housing about the axis of the bearing standard in order to move the seaming head into and out of cooperative relation with the machine turret soas to facilitate inspection and adjustment of the parts of the seaming mechanism. In order to suitably support the seaming head during swinging thereof between operative and inoperative positions and for avoiding the setting up of twisting strains in the seaming mechanisms in the head, there is provided a supporting lug 31 on the lower head section 21 adapted to be supported upon and ride over an arcuate track 38 extending upwardly from the frame shelf portion 1. A forked lug 39 also projects from the lower housing section and is engageable by a quick detachable pivot screw 40 supported on the machine frame and which may be utilized to secure the seaming head in the operative relation with the turret illustrated in Figure l of the drawings. See also Figure 4.

It will be observed by reference to Figure 3 of the drawings that a shaft member 4| is affixed in the hub 35, and a sleeve 42 is freely rotatable about this shaft within the hub. The sleeve carries a spur gear 43, a slightly larger spur gear 44 and a bevel gear 45. Rotation is imparted to the bevel gear 45 and the sleeve to which it is afilxed by a bevel gear 46 aflixed upon the through the opening 5| and is removably secured to the ears 52 as at 55. See Figures 1 and 2.

A mounting sleeve 56 is key-secured in the sleeve 53 as at 51 and projects at both ends from said sleeve. One end of the sleeve 56 extends into the bell portion 3| of the housing and is externally threaded at its other end to receive a clamp nut 58. Within the bell portion 3| of the housing, the sleeve 56 carries or is keysecured to a plate enlargement 59. See Figure 2.

The plate 59 is opposed by a circular composite plate Bil which is suitably secured thereto. An oblong or generally square chuck 6| is removably secured centrally to the plate 60 through the medium of screw equipments 62, and suitable key equipments 63 are interposed between the chuck 6| and plate 60 to further insure against relative movements between these parts. The chuck includes a recess in its bottom face, for receiving a knockout pad 64, and a suitable slide guide socket for receiving the positioning pin 65 secured to and projecting upwardly from the pad. The plate 60 is equipped with a cam grooveway 66 surrounding and following the shape of the chuck 6|. See Figures 2 and 5.

A knockout rod 61 is reciprocably mounted in the sleeve 56 and extends beyond the externally threaded end of that sleeve. At its extended end the rod is connected to the upper end of v a lever 68 pivoted intermediate its ends as at 69 on a bracket 10 secured to the hub 34. At its lower end, the lever 68 is connected by a quick detachable connection II with a link 72 pivoted to a thrust member 13 slidable in bearings 14 provided therefor in the machine frame and carrying a roller 15 engaged in a suitably shaped groove in a plate cam 16 rotatable with the shaft la. The groove in the cam 16 is so shaped and the rotation of the cam so timed that the knockout pad 64 and the rod 61 on which it is carried will be actuated at the proper time in each seaming operation rolls 94v and the edge of the container cycle for suitably displacing the seamed container from the chuck. See Figure 1.

Anti-friction bearings 11 are disposed in spaced relation about the mounting sleeve 56 and rotatably support a seaming head rotor and gear assembly including a gear sleeve I8 equipped at its end with a gear portion 19, and a sleeve 89 telescopically surrounding the sleeve I8 and keyed thereto as at 8|. The sleeve 89 carries a belllike seaming head or rotor 82 which is recessed as at 83 to receive and rotate about the plate assembly59, 69 and includes an outwardly extended base flange 84 and four equidistantly spaced bearing portions 95. Each bearing hub portion 85 is opposed by a removably mounted bearing member 86 which cooperates with the hub portion in providing a lever hub receiving bearing, as shown in Figures 2 and 5 of the drawmgs.

A lever and arm assembly is oscillatably mounted in each of the bearings 85, 86 and each assembly includes a sleeve hub 81 oscillatable in the respective bearing, and a lever 88 rigidly secured to the hub and projected inwardly to overlie the cam groove 66, said inwardly projected end being equipped with a roller 89 which rides in the cam groove to impart movement to the lever as the rotor or head 82, 84 rotates about the cam plate 69. Each lever 88 carries a seaming arm 99 which is pivotally mounted on the lever intermediate its ends as shown in Figure 5. Each arm is supported on a pivot pin 9| secured to the respective lever 88, and an eccentric sleeve 92 surrounds each pin and is adjustable thereabout in a receiving bore formed in the respective arm, suitable clamping means 93 being provided for securing the sleeve in its adjusted positions. By adjusting the positions of the eccentric sleeves the angular relation of the levers 88 and arms 99 can be altered and the positions of the seaming rollers relative to the chuck can be suitably varied. A seaming roller 94 is removably secured as at 95 at the free end of each arm 99, and a pin 96 projects from the lever or arm of each set into a receiving slot in the companion lever or arm where it engages a spring 91 housed in a receiving bore 98 and constantly tending to move the arm relative to the supporting lever 88 in a direction away from the chuck.

A shaft 99 is rotatably mounted in each lever hub 81, and each shaft 99 has 'a spur gear I99 affixed to one end and a seaming arm actuator cam I 9| secured at its other end, as shown in Figures 2, 5, 6 and 7 of the drawings. Each cam is engageable with a removable and replaceable tappet I92 carried by the respective seaming arm 99. The spring and pin equipments 96, 91 urge the seaming rolls 94 away from the chuck 6I and the tappets I92 against the controlling surfaces of the actuating cams I9I.

Rotation is simultaneously imparted to all of the cam actuating gears I99 by a spur gear rim I93 carried by a sleeve I94 rotatable about the telescoped sleeves I8, 89 within the packed housing hub portion I95. See Figures 2 and 5. The sleeve I04 includes a gear extension I96 to which rotation is imparted by the gear 43 hereinbefore referred to. Rotation is imparted to the sleeves I8, 89 and the rotor 82 by intermeshing of the gear portion 19 with the gear 44 hereinbefore referred to.

Each of the two cams I9I serving to control operation of the first operation rolls includes a reduced diameter or clearance surface for effecting a clearance between the respective first closure member to be rolled intoa seam. See Figures 5, 6 and 8. This clearance surface, designated I91, extends over 180 of the circumference of the cam, and the amount of clearance between the innermost portion of this surface and that portion effective to bring about first contact between the seaming rolls and the edge of the end closure amounts to .118. The remainder of the effective surface of this cam comprises three distinct step and dwell portions, each dwell portion extending over 60 of the circumference of the respective cam. The first step, designated I98, effects a lift or actuator element movement of .031, and the concentric dwell following this step is designated I99. The second step, designated I I9, effects a lift or actuator element movement of .028, and the concentric dwell following this step is designated III. Similarly, the third step, designatedl I2, effects a lift or actuator element movement of .028, and the concentric dwell following this lift is designated I I3. See Figures 6 and 8 of the drawings.

Each of the two cams which control operation of the second operation rolls includes a clearv ance portion designated H4. This portion extends over 254 of the circumference of the cam and the amount of clearance between the innermost portion of this surface and that portion eifective to bring about first contact between the seamingrolls and the seam amounts to .228. Each of these cams includes a single step portion II5 effective to move the seaming rolls .030 toward the chuck and this step is followed by a concentric dwell portion II6 extending over 106 of the circumference of the cam. See Figures 7 and 9 of the drawings.

Each set of two cams for controlling the operation of the opposed first and second operation rolls are set to cause said rolls to effectively engage the seam simultaneously.

The cam plate 69 may be provided at one portion thereof outwardly defining the cam groove 68 with a wall portion III removably mounted as at I I8. be provided with a plurality of outlet ways II9 each formed in the shape of an arc struck from the center of one of the bearing hubs 85, 86. By reason of the provision of these equipments the wall portion II! can be removed and by suitably manipulating the rotor relative to the plate 69 so as to bring the removed wall portion in register with a selected one of the outlet ways H9, the particular lever and arm set 88, 99 can be swung outwardly about its pivotal mounting 81, 99 so as to render all parts of the set readily acessible for manipulation or adjustment. During the outward swinging of the set the respective cam rollers 89 may pass out through the outlet way II9 and through the open hinged housing cover section as indicated in dotted lines in Figure 5.

In Figures 10 to 14 of the drawings there are diagrammatically illustrated successive steps .in

will be noted that at point a the seaming roll.

is still spaced from and out of engagement with (See Fig. 5.) The rotor 82, 84 may the extended edge portion of the end closure as illustrated in Figure 10. Figure 11 indicates the condition at point 11 whereat first contact between the seaming rolls and the edge of the end closure is effected. In Figure 1.2 the seaming roll is illustrated as having efiected the first edge turning step. This condition will pertain throughout the first dwell portion as at c and until the second step is engaged. Figure 13 illustrates the second edge turning step effected by the second cam step and this condition of the parts pertains throughout the second dwell portion as at d and until the third step is approached. At the third step, point e, the final turning of the seam is effected, and the setting of this final seam turn by the third concentric dwell portion finishes the first operation. See Figure 14.

In Figures 15 through 1'7 of the drawings there are diagrammatically illustrated the successive steps in the second seaming operation, the three successive steps indicating the positions of the seaming rolls and the seam being formed thereby when the tappets I02 of the respective seaming arms 9i! are being engaged at points successively designated a, b, and c, on the second operation controlling cams. These point designations are applied to the diagrammatic development of these cams illustrated in Figure 9. It will be noted that at point a the seaming roll is still spaced from and out of engagement with the extended edge portion of the seam as illustrated in Figure 15. Figure 16 indicates the condition at point I)- whereat first contact between the seaming roll and the seam is effected. In Figure 1'? the seaming roll is illustrated as having completed the edge turning operation. This condition of the parts will pertain thorughout the contact with the dwell portion II6 as indicated at 0 thereby setting and completing the seam.

As the loosely assembled container body and end closure are presented at the securing station as illustrated in Figure 1 of the drawings, the chucking pad 82 is moved to the right as illustrated in this figure to force the loose assembly against the chuck BI so that the sets of first and second operation seaming rolls can properly turn the edge of the end closure and seam-secure it to the container body. Upon completion of each seaming operation and before the turret is indexed to present another container body and end closure at the securing station, the knockout rod 61 is actuated to force the knockout pad 64 against the container for returning it to its initial position illustrated in Figure 1.

It will be obvious by reference to Figures 1, 3 and dof the drawings that by removing the quick detachable securing screw from engagement with the forked lug 39 the seaming head can be swung about its pivotal mounting 33, 8 whenever it is desirable to remove the head from the cooperative relation with the turret illustrated in Figure 1 of the drawings for the purpose of rendering the mechanisms within the head housing or those mounted on and associated with the turret accessible for adjustment or replacement and the like. This displacement of the head is greatly facilitated by the off-center position of the pivot axis, and the accessibility of the mechanisms within the head are additionally facilitated by the hinge mounting 32 of the upper portion of the housing. Because of the nature of the driving connection between the power shaft 9 and the seaming mechanisms within the head, swinging of the head about its pivotal mounting can be effected without disrupting these driving connections or their synchronized relation to the other mechanisms of the machine.

In this disclosure repeated reference is made to square or generally square containers but it is to be understoodthatthe invention is not limited to seaming apparatus designed for seaming square containers alone. The problem of providing seams uniformly tight throughout the whole circumference of the container is presented in the seaming of containers of various forms wherein certain edgeportions turn on radii shorter than other radii of seam edge portions on the same container, and the present invention remedies these problems and comprehends all seaming mechanisms defined by the appended claims.

In Figure 18 of the drawings there is illustrated an adjustable form of tappet which can be substituted for the tappet I02 hereinbefore described. The tappet, designated, I20 is pivotally supported as at I2I on the respective seaming arm I22 which isin turn pivotally mounted as at I23 on the supporting arm I24 and engages the adjacent control cam I-IlI. A limiting screw I25 is mounted on the arm I22, and a screw member I26 may be adjusted in a threaded bore in the tappet member for drawing said member against the adjustable limiting screw. By this means the relation of the seaming roller carried by the arm I22 to the chuck can be varied to suit differen conditions of use.

It will be apparent from the foregoing description that the invention features the particular manner of mounting 'and driving the seaming head and the seaming mechanisms housed therein, the shaping of the first operation control cams to include a plurality of successively effective definite steps and roll holding or seam setting dwell portions, the formation of the first operation seaming rolls of the same size, and actuation of the diametrically opposed rolls of each cooperating pair of the first and second operation roll sets so that the opposed rolls of each set simultaneously engage the seam being formed.

While the gear ratios and the proportions of cooperating parts may be altered to suit particular demands of use, the controlcams illustrated in Figures'fi to 9 each make two turns per machine cycle; One of these turns occurs while a loosely assembled container is being moved into proper position to be engaged by the seaming rolls, and during the other turn the actual seaming operations take place and the finished product of the seaming function is moved away from the chuck. Thus since each step dwell portion of the first operation control cam extends over 60 of the circumference, each such dwell portion equals one-half turn per roll and said dwell portions collectively cover one and'one-half turns per rollseaming contact or three seam turns.

In the particular disclosure herein made as an example of embodiment of 'the invention, the parts are so proportioned and correlated that the seaming head rotor makes six turns during each seaming operation or can seaming cycle, and each of the seaming control cams makes two turns for each six turns of the rotor, or one turn for each can seaming operation and one turn during placement of the can to be seamed and displacement of said can after it has been seamed.

It is to be understood, of course, that the details of structure and arrangement of parts may be variously changed and modified without departing from the spirit and scope of the invention.

We claim:

1. In a seaming head construction, a stationary chuck, a rotor rotatable relatively to said stationary chuck, shafts carried by and journaled on the rotor, a first lever and a second lever on the rotor each having a swinging movement independently of the rotor on the axes of the respective shafts and having cam follower cooperation with said stationary chuck, an arm pivoted on each lever, a first operation seaming roll mounted on said first lever carried arm and opposed to said chuck, a second operation seaming roll mounted on the second lever carried arm and opposed to said chuck, cams fixed on said shafts and engageable with the arms for providing pivotal motion of the arms independent of that of the levers, said cams being of different contour, the cam associated with the arm carrying the first operation seaming roll having a plurality of steps each effective to force the associated seaming roll a definite step distance against the seam being formed and each followed by a concentric dwell portion effective to hold the associated seaming roll for an interval against the seam being formed, and the cam associated with the arm carrying the second operation seaming roll having a single step effective to force the associated seaming roll a definite step distance against the seam being formed and followed by a concentric dwell portion effective to hold the associated seaming roll for an interval against the seam being formed.

2. In a seaming head construction, a stationary chuck, a rotor rotatable relatively to said stationary chuck, four shafts carried by and journaled on the rotor with their axes of rotation parallel to that of the rotor, a pair of first levers and a pair of second levers on the rotor each lever having a swinging movement independently of the rotor on the respective axes of said shafts and having cam follower cooperation with said stationary chuck, an arm pivoted on each lever, a first operation seaming roll on each arm of the first levers, the two first operation rolls being in opposed relation, a second operation seaming roll on each arm of the second levers, the last mentioned two rolls being in opposed relation, a cam for each arm of the first levers and a cam for each arm of the second levers fixed each on the shaft on which its corresponding lever is mounted and engageable with the respective arm for providing pivotal motion of the arms independent of that of the levers, the cams for the arms on the first operation levers being of different contour from those of the cams for the arms on the second operation levers, each cam associated with an arm carrying a first operation seaming roll having a plurality of steps each effective to force the associated seaming roll a definite step distance against the seam being formed and each followed by a concentric dwell portion effective to hold the associated seaming roll for an interval against thesea'm being formed, and each cam associated with an arm carrying a second operation seaming roll having a single step effective to force the associated seaming roll a definite step distance against the seam being formed and followed by a concentric dwell portion effective to hold the associated seaming roll for an interval against the seam being formed.

3. In a seaming head construction, a stationary chuck, a rotor rotatable relatively to said stationary chuck, shafts carried by and journaled on the rotor, a first lever and a second lever on the rotor each having a swinging movement independently of the rotor on the axes of the respective shafts and having cam follower cooperation with said stationary chuck, an arm pivoted on each lever, a first operation seaming roll mounted on said first lever carried arm and opposed to said chuck, a second operation seaming roll mounted on the second lever carried arm and,

opposed to said chuck, cams fixed on said shafts and engageable with the arms for providing pivotal motion of the arms independent of that of the levers, said cams being of different contour, the cam associated with the arm carrying the first operation seaming roll having three steps each effective to force the associated seaming roll a definite step distance against the seam being formed and each followed by a concentric dwell portion effective to hold the associated seaming roll for an interval against the seam being formed, and the cam associated with the arm carrying the second operation seaming roll having a single step effective to force the associated seaming roll a definite step distance against the seam being formed and followed by a concentric dwell portion effective to hold the associated seaming roll for an interval against the seam being formed, a gear on each shaft, and means for rotating the rotor and gears.

4. In a seaming head construction, a stationary chuck, a rotor rotatable relatively to said stationary chuck, four shafts carried by and journaled on the rotor with their axes of rotation parallel to that of the rotor, a pair of first levers and a pair of second levers on the rotor each lever having a swinging movement independently of the rotor on the respective axes of said shafts and having cam follower cooperation with said stationary chuck, an arm pivoted on each lever, a first operation seaming roll on each arm of the first levers, the two first operation rolls being in opposed relation, a second operation seaming roll on each arm of the second levers, the last mentioned two rolls being in opposed relation, a cam for each arm of the first levers and a cam for each arm of the second levers fixed each on the shaft on which its corresponding lever is mounted and engageable with the respective arm for providing pivotal motion of the arms independent of that of the levers, the cams for the arms on the first operation levers being of different contour from those of the cams for the arms on the second operation levers, each cam associated with an arm carrying a first operation seaming roll having three steps each effective to force the associated seaming roll a definite step distance against the seam bein formed and each followed by a concentric dwell portion effective to hold the associated seaming roll for an interval against the seam being formed, and each cam associated with an arm carrying a second operand gears.

ALFRED L. KRONQUEST. OTTO A. SCHMITT. 

